In various kinds of transmission and communication system, it is necessary to transmit and receive a large number of data correctly. Particularly, it is an important subject in the wireless communication system or the channel communication system with long distance to receive the digital data reliably and errorlessly. In order to communicate a message or a data, certain channels are adopted to transmit therethrough, however, a digital data usually cannot be received correctly and reliably and an error is occurred because of the defects of the channel hardware, the interference from the external environment, the dissipation of the power, multi route decay, noise, and/or sensitivity of the electronic equipment. Hence, a reliable data transmission is difficult and important.
In order to improve the reliability of the channel data transmission, various methods have been developed, for example, the Forward Error Correction (FEC) code and the corresponding apparatus are adopted for positioning, offsetting, correcting and/or eliminating the errors, wherein many pre-determined codewords are established according to an encoding manual with a specific encoding format for encoding the information data needed to be transmitted. Accordingly, the errors introduced in the transmission process are able to be located and corrected in the decoding procedure via some developed mathematical method.
In the course of the information transmission, the information encoder converts the primitive information to a set of binary codes (bits), which is called as an information sequence u. The broadly-defined “encoding” includes A/D conversion (ADC), source coding and channel encoding etc. The channel encoding technique promotes the reliability of the digital communication by processing an error control of the digital signal, and the quality and quantity of the transmission are promoted. An information sequence is converted to a separated encoded sequence v, which is named as a codeword.
Generally a codeword v is still a sequence of the binary numbers, but sometimes the non-binary numbers is applied in some application. Every codeword can be regarded as a vector in a space having n dimensions, and each bit in the codeword is equal to each component value of the vector. For example, a codeword “101” can be represented by a one-dimensional code vector x=(101)
The number of the components which is different in any two codewords is defined as the Hamming distance dH of the two codewords, for example, the Hamming distance dH (x, y) of the two code vector x(101) and y(110) is 2, because the second component and the third component therein are different. As to a well-designed encoding system, the minimum Hamming distance between the effective codewords named as a minimum Hamming distance “dmin,”, which is the allowed number of error bits while decoding, namely, an error can be detected when the number of the error bits less than the value of dmin.
A general decoding method is processed by taking the codewords closest to the received information data by a correlation operation, wherein the correlation operation of two vectors is defined as the multiplying product of the corresponding components therein, for example, the correlation operation (represented by the symbol “⊕”) of the vectors x(x1, x2, x3 . . . xn) and y(y1, y2, y3, . . . yn) can be represented as followed:x(x1, x2, x3 . . . xn)⊕y(y1, y2, y3, . . . yn)=x1*y1+x2*y2+x3*y3 . . . xn*yn 
In a binary system, the larger the result of the correlation operation of a received information data and a codeword is, the more the received information data is closing to the codeword, namely, the codeword is more closing to a correct solution of the original data. If the transmitted block code is provided with some specific characteristic, such as linearity or periodicity, the complexity of the decoding process can be largely reduced. However, if the transmitted block code is not provided with any specific characteristics for reducing the complexity of the decoding process, we have to take the correlation operation of the received information block data with all the predetermined codewords to find the codeword with max correlation operation result being the solution code.
As the length of the block code gets longer (i.e. the number of the bits therein goes larger), the amount of the correlation operation goes larger, and thereby the efficiency of the channel decoding is influenced. In order to reduce the amount of the correlation operation and the load of calculation, only the codewords having distance from the received information data in the range of the minimum Hamming distance dmin are adopted for correlation operation, which is called a “bounded distance decoding”.
However, with the increasing of the amount of information data, and the requirement of fast and accurate transmitting, the efficiency of the prior decoding methods is still dissatisfying. Therefore, a simpler and more efficient decoding method without influencing the reliability of the channel transmission is demanded urgently.
From the above description, in order to overcome the drawbacks in the prior art, a block code decoding method and device thereof are provided by the present invention via the devoting research and perseverant work.